Dodging Day Zero – multiple water sources for multiple uses

How many sources of water do you use on a daily basis? If you live in the developed world, chances are you only use one – a treated, piped, well-distributed source coming from a reservoir or groundwater reserve.

In many parts of the developing world, these types of highly developed water resources are not available. Instead, households need to make the most of their own capacity to gain access to water. This might be in the form of harvesting rainwater (in buckets, pots or tanks), collecting water from local wells or stand pipes which are often hundreds of metres away from the home, or from a natural source, like a river or a spring.

Rather than just relying on one of these alternative water sources, our recent research (http://bit.ly/2st1L0n) has highlighted that many households use multiple sources of water every day to meet the demands of their family life. Even in freshwater scarce settings like remote coral atolls in the Pacific, where there is no surface water, we found that families use between 2 and 5 sources of water every single day.

So why do households use multiple sources of water? Well, the simple answer is that they seek to make the most of a scarce and variable resource. To do this, households often prioritise the use of high quality sources, like rainwater, for drinking, and then use other sources, like water from rivers and wells, which may be more vulnerable to contamination, for other household activities like washing, cooking and cleaning.

The most obvious benefits of using multiple water sources is that households don’t use the most precious high quality water for activities that don’t require such a high quality source. This means that the best source of freshwater can last longer, because it is only used for drinking.

We have also learnt that multiple water sources help households build resilience to climate variability such that they can survive throughout the year. We found that households cope during dry times by switching between different water sources and by modifying their water consumption patterns accordingly. In some households, austere use of water helps make a scarce resource available for much longer, even during extended periods of drought.

For those of us living in the developed world, with our single, piped, reliable source of water, it is worth pondering what might happen should our supply dry up. This is particularly relevant right now as Cape Town, in South Africa, approaches Day Zero – the day where the city effectively runs out of water – http://bit.ly/2s4a9mG – has our heavy reliance on a single source of water increased our exposure and vulnerability to extreme drought?

The response to droughts in the developed world does already show signs of a switch towards recognising the need for more than one source of water. In south-east Queensland, Australia, severe droughts over the past decade have driven significant investments in water use education as well as the infrastructure needed to join multiple sources of water to the piped water grid – http://bit.ly/2Eh6dED. This has included desalination plants near the coast, recycled and wastewater treatment schemes and the expansion of the gridded network of pipes – such that water can be transferred between all major reservoirs in the region.

Ultimately, the key to water security lies not just in a piped network and treatment facilities, but through recognition of the various sources of water available and their inherent qualities like volume, recharge rates, water quality and accessibility. Multiple water sources hold the key to resilience in remote communities in the Pacific, but as the climate changes and extreme droughts become the norm, they will likely be needed to support those of us living in developed cities as well.

In light of the importance of water and its relevance to all of us, we will be discussing the issue of multiple water source use and patterns of seasonal switching between water sources at the upcoming WASH FUTURES Conference in Brisbane in March 2018 – http://washfutures.com/ We will draw on evidence from all around the world to highlight the need to think about multiple sources and the role they can play in sustaining lives and livelihoods in a rapidly changing world.